1``constant``
2============
3
4.. versionadded: 1.12.1
5    constant now accepts object instances as the second argument.
6
7.. versionadded: 1.28
8    Using ``constant`` with the ``defined`` test was added in Twig 1.28.
9
10``constant`` returns the constant value for a given string:
11
12.. code-block:: jinja
13
14    {{ some_date|date(constant('DATE_W3C')) }}
15    {{ constant('Namespace\\Classname::CONSTANT_NAME') }}
16
17As of 1.12.1 you can read constants from object instances as well:
18
19.. code-block:: jinja
20
21    {{ constant('RSS', date) }}
22
23Use the ``defined`` test to check if a constant is defined:
24
25.. code-block:: jinja
26
27    {% if constant('SOME_CONST') is defined %}
28        ...
29    {% endif %}
30